.container {
    height: 56px;
    box-sizing: border-box;
    padding-top: 15px;
    border: 1px solid #ccc;
    text-align: center;
    /* 吸顶 开始的样式*/
    position: sticky;
    top: 0px;
    background:#ccc;
    /* 吸顶结束*/

    box-shadow: 0 2px 4px rgba(0,0,0,0.12);
}
.item {
    display: inline-block;
    color: #333;
    text-decoration: none;
    line-height: 22px;
    margin-left: 100px;
    font-size: 16px;
    cursor: pointer;
}

.item:hover{
    color: #999;
}